Clark had previously been involved in several spectacular smashes in his 15-year racing career, but had always escaped serious harm.

Experts suggested the crash was caused a faulty steering mechanism or rear-axle suspension.

The 80,000 racing fans who had been watching the race were informed of the tragic crash over the loudspeaker. Stunned by the news, they spontaneously rose to their feet in a silent tribute.

A track marshal who was the only witness to the crash said: "I was horror-struck. Everything happened so fast. The car skidded off to the left and seemed to dive through the fence only 10 yards (9.14m) from me.